Chairs and seats



C. A. RIDDER CHAIRS AND SEATS March 12, 1963 Filed Dec.

6 Sheets-Sheet 1 INVENTOR CLARA ANN RIDDER a ig? iiees ATTORNEYS March12, 1963 c. A. RIDDER 3,081,129

CHAIRS AND SEATS Filed Dec. 16, 1960 6 Sheets-Sheet 2 '0 Q AQEE INVENTORCLARA ANN RIDDER 371 gr .1 r

ATTORNEYS March 12', 1963 c. A. RIDDER 3, 2

CHAIRS AND SEATS Filed Dec. 16, 1960 6 Sheets-Sheet 3 FEDCBAABCDEF VBYgpu flaz aflaw ATTORNEYS 6 Sheets5heet 5 Filed Dec. 16, 1960 3INVENTOR CLARA ANN RIDDER ATTORNEYS March 12,1963 c. A. RIDDER CHAIRSAND SEATS 6 Sheets-Sheet 6 Filed Dec. 16, 1960 /H 0 B o U M 9 /o/8 /a IIllll O l/0 I l I I o /0 0/ 0 O 0 /O/ /2 o o A INVENTOR CLARA ANN RIDDERATTORNEYS United States Filed Dec. 16, 1960, Ser. No. 76,321. 2 Claims.(Cl. 297-452) The present invention relates to improvements in chairsand seats The invention. is more particularly concerned with providingchairs and seats which provide support to the. body of. a seated. personin a manner to provide true comfort.

Chairs and seats produced in-the past have too often been designed withfactors such as appearance, cost and structural strength as thedominating factors with little or no real attention being given to theactual comfort of. the user.. This hasresulted in chairs and seats whichoften contort the body into uncomfortable and even unhealthy positions.So far as I am aware, there has not heretofore been any truly scientificstudy of the characteristics of a chair or'seat which contribute to ordetract from the comfort of the user. The present invention is theresult of exhaustive research into those characteristics of chairs. orseats which are essential to true comfort. Such characteristics werefound to include the height of the seat, the slant of the seat, thedepression or three-dimensional contours of the seat, the slant of thechair back, the depth of the back and the three-dimensional contour ofthe chair back; The most important characteristic contributory tocomfort was found to be the relationship in space of the seat and itscontours to the back and. its contours. These characteristics andrelationships are important only in the body contacting portions of theseats and backs. The portions of the seats and backs which do notcontact the body may assume a wide variety of shapes and configurations:It is thus possible for a chair or seat to incorporate myimprovementsand tohave any desired overall appearance.

It is therefore the primary object of the invention to provide chairsand seats which furnish true comfort to users thereof.

A further object of the invention is to provide different chairs orseatswhich will provide true comfort in each ofithree basic types ofsitting positions preferred by adult persons.

The. foregoing and otherobjects and advantages of the invention will bebetter understood from the following description which has reference tothe accompanying drawings, wherein:

FIGURE 1 is a perspectiveview of a test chair used inobtaining the datautilized in the production of the chairs and seats of the invention;

FIGURE 2 is a fragmentary vertical sectional view through the center ofa test chair after completion of a typical test;

FiGURE 3 is an enlarged fragmentary vertical sectional view of aportion'of the seat'of the test chair;

FIGURE 4 is a sectional view taken in; the direction of the arrowsalongthe line 4-4 of FIGURE 3;

FIGURE 5 is an enlarged fragmentary vertical sectional View of a portionof "the back of the test chair;

FIGURE 6 is an enlarged sectional View taken in the direction. of thearrows along the line 6-6- of FIG- URE .5;

FIGURE7 is a schematic side elevationalview showing the manner ofmeasuring the positions in space of certain' elements of the seat andback of the test chair;

FIGURE 8 is perspective viewof a'straight chair embod'yihg the"invention;

FIGURE 9 is a diagram showing, the longitudinalconatent lid tours of theseat of the chair of FIGURE 8 along the lines A to F;

FIGURE 10 is a diagram showing the'transverse con toursof the seat ofthe chair of FiGURE 8 along the lines 1. to 11;

FIGURE 11 is another perspective view of the chair of FIGURE 8;

FIGURE 12 is a diagram showing the-transverse contours of the back ofthe chair of FIGURE 11 along the lines 1 to 9;

FIGURE T3 is a diagram showing the vertical co'ntours of the back of thechair of FIGURE 11 alonglthe lines A to D;

FIGURE 14 is a perspective view of an occasional chair embodying theinvention;

FiGURE 15 is a diagram showing the horizontal contours of the back ofthe chair of FIGURE 14 along the lines 1 to'9;

FIGURE 16 is a diagram showing the vertical contours of the back of thechairof FIGURE 14 along the lines A to D;

FIGURE 17 is a perspective view of portions of a chair for relaxing;

FIGURE 3.8 is a diagram showing the longitudinal contours of the seat ofthe chair of FIGURE 17 along the lines A to F;

FIGURE 19 is a diagram showing the" transverse co'ntours of the seat ofthe chair. of FIGURE 17' along-the lines 2. to 12;.

FZGURE 20 is a perspective view of other portions" of the chair ofFIGURE 17;

FIGURE 21 is a diagramv showing the vertical contours of. back of thechair of FIGURE 20 alon'gthe lines A to D; and

FIGURE 22 is a diagram showing the horizontal contour lines of the chairof FIGURE 20 along the lines 1 to 15.

The test chair is designated generally by the reference numeral 30. Itincludes'a base 31 on which is supported a seat assembly 32 by means ofthree hydraulic jacks 33', as and 35 which can be adjusted in height tovary the heightand slope of the seat assembly.

The actual body contacting portion of the seat assembly consists of theupper ends of a plurality of spring loaded plungers 36 which arearranged in longitudinal and transverse rows, as clearly shown inFIGURE 1. Each seat plunger Bio-extends through an opening in plate 37-and is provided'with an upper flange 38 to. which is attached a-ruhhercap 39. A compression spring member 40 surrounds each plunger 36 betweenthe plate 3'7 and the flange 33. The plungers' 36 are spaced one andone-half inches apart from center to center in the longitudinal andtransverse rows; The caps 39 are one and one-quarter inches in diameter.There is thus provided a substantially continuous body supportingsurface composed of the caps 39 which are individually movable bycompres sion of the associated springs 40. All of the springs 40 are ofan equal strength of five pounds. A clamping bar 41 is slidablysupported alongside each'longitudinal row of plungers. Each clamping barhas a camming surface 42 adjacent each plunger 36 in its associatedlongitudinal row; FIGURE 4 illustrates the camming bar 41 in a positionto permit vertical movement of its associated plungers and'the cammingbar 41d in a position to clam v 7 its associated plungers. againstmovement.

A back assembly 43 is pivotally secured to the seat assembl' 32 by'pivotpins 44 which can be positioned in any desired openings 45 to adjust theeifectivelength of the seat portion 32. Braces46 are pivotally secured'to the upper end of the back at 47. The lower ends of the braces'45 areprovidedwith a' plurality of openings 48.

The seat assembly 3'2 is similarly provided with a plurality of openings49. Pins 5t pass through the desired openings i8 and 49 to obtain anappropriate slant of the chair back.

The back assembly 43 is provided with a plurality of independentlymovable plungers 51. These back plungers extend through aligned openingsin plates 52 and 53 of the back assembly. Each plunger 51 is providedwith a row of longitudinally spaced depressions 54. Mating cavities inthe plates 52 and 53 between each pair of plungers 51 receive steelballs 55 and 56. A small compression spring member 57 urges the ballstoward the plungers 51, as best shown in FIGURE 6. The plungers 51 willbe locked against longitudinal movement when in the positions shown inFIGURE 6, but slight rotational movement of any plunger releases it andit can then be manually moved longitudinally. It will be seen that eachplunger 51 can be moved independently of the other plungers.

The plungers 51 are provided with flanges 58 to which are secured rubbercaps 59. The plungers 51 are spaced one and one-half inches on centersin the vertical and horizontal rows. The caps 59 are one and one-quarterinches in diameter. The plungers 51 may be retracted to position theflanges 58 and the caps 59 in recesses 69 in the plate 53. The upperplunger 51 is shown in such position in FIGURE 5 and it will be seenthat the face of the cap 59 is flush with the surface of the plate 53.

A large number of adult men and women were used as subjects for test inthe test chair. The subjects were selected so that the total numberwould be as representative as possible of the height and weightdistribution of the total adult population. Each subject was tested inthree assumed sitting positions by appropriate adjustments of the heightand slope of the seat assembly and of the position and slant of the backassembly. These sitting positions corresponded to: (1) Dining or writingas in a straight chair; (2) Playing table games or talking as in anoccasional chair; and (3) Reading or relaxing as in an easy chair asdistinguished from a lounging chair.

Each subject was seated in the test chair and adjustments were made ofthe height and slope of the seat and of the position and slant of theback to make the individual comfortable for the particular sittingposition under test. The clamping bars 41 were in positions to permitmovement of the seat plungers 36. The back plungers 51 were then movedindividually and locked in those individual positions in which theircaps 59 provided the most comfortable support to the back of thesubject. After proper adjustment of the plungers 51 had been completed,the clamping bars 41 were moved to clamp the plungers 36 in theindividual positions they had assumed by virtue of their depression bythe weight of the seated subject.

The subject then arose from the chair while the plungers 36 and 51retained their clamped or locked positions. The position of each plungerwhich had been engaged by the body of the subject was then determined inthe manner illustrated in FIGURE 7. An upright, calibrated standardsupported a horizontal bar 62 which was positioned in turn over eachlongitudinal row of plungers 36 and the height of the upper surface ofeach cap 39 was measured and recorded. The standard 61 also carried ablock 63 having a face 64- which was vertically above the front edge ofthe seat. A calibrated bar 65 extended through the block 63 toward theback assembly. By horizontal and vertical movement of the block 63 andhorizontal movement of the bar 65 it was possible to determine andrecord the positions of the front surfaces of the caps 59.

FIGURE 2 illustrates typical positions assumed by the middlelongitudinal row of caps 39 of the seat assembly and by the middlevertical row of caps 59 of the back assembly upon completion of a test.It will be seen that a smooth curve has been drawn along the surfaces ofthe caps. This curve is shown dotted at 66 in the gap between the seatand the back. The tests revealed that no body support was necessary ordesired in this zone. For that reason, there may be a gap between theseat and the back in the chairs of my invention. If the design of thechair permits no such gap, the chair should curve back in this zone atleast as far as shown by the dotted line at 66.

The data obtained from the tests of all subjects was tabulated for eachof the three sitting positions. Gratifying uniformity or similarity wasfound in the data for each of the three sitting positions. It was foundpossible to average the data for each sitting positon and to arrive atchairs for each sitting position which are comfortable to the vastmajority of the adult male and female population.

FIGURES 8 to 13 illustrate a chair for dining or writing and which canbe termed a straight chair. The points on the diagrams illustrate theaverage positions assumed by the caps 39 and 59 during the tests. Thecontour lines A to F of FIGURE 9 correspond to similarly designatedlines in FIGURE 8. Although the contour of only one-half of the seat hasbeen shown in FIGURE 9, it will be understood that the two halves aresymmetrical. The contour lines 1 to 11 of FIGURE 10 correspond tosimilarly designated lines in FIGURE 8. The slant and contour of theback of the straight chair are simiportions of the back of the chairwhich are not contacted by the body. The contours of such portions ofthe chair are of no significance to the chairs comfort and may varywidely as dictated by design considerations.

It will be seen that I have provided chairs having contourscorresponding to those assumed by the plunger caps 39 and 59 when theplunger caps 39 are depressed against the action of the spring members40 while the subject's back is firmly supported by the plunger caps 59.

The invention is applicable to seats of soft or hard material. The hardseats may be made of molded or otherwise shaped wood, plastic or metal.A thin cushion can be used over the hard material without loss of thesignificant advantages of the invention. In chairs or seats havingsprings or thick cushions the construction should be such that thecontours described herein are assumed when the chair is occupied. Inmultiple seating units such as benches or sofas it will not be possibleto have the described contours transversely of the body but the contourslengthwise of the body will be found to add greatly to comfort.

I have illustrated and described what I consider to be the preferredembodiments of the invention.

I claim.

1. A chair having body supporting seat and back portions, said portionshaving three-dimensional contours and relative positions substantiallycorresponding to the contours and positions determined for a personassuming a particular type of sitting position, said seat portionposition substantially corresponding to the seat portion height andinclination adjusted to the comfort of the seated person, said backportion position substantially corresponding to the back portioninclination and positioning, relative to the seat portion positioning,adjusted to the comfort of the seated person; and the seat and backportion contours substantially corresponding to contours adjusted to thecomfort of the seated person, with the back portion having athree-dimensional contour substantially corresponding to that formed bythe exposed forward ends of a plurality of unbiased, mutuallyindependent, closely spaced and forwardly extending back plungers,movable to individually adjusted positions, when such back plungers havebeen individually manually adjusted to unyieldingly and independentlyengage and firmly support the back of the seated person in a comfortableposition, and with the seat portion having a threedimensional contoursubstantially corresponding to that formed by the upper surfaces of aplurality of mutually independent, closely spaced and verticallydisposed seat plungers which are independently movable and equally andindividually resiliently urged upwardly when the person is seated on theexposed upper surfaces of said seat plungers while the persons back isfirmly supported by said back plungers in the manner described.

2. A chair having body supporting seat and back portions, said portonshaving three-dimensional contours and relative positions substantiallycorresponding to the average contours and positions determined for aselected group of persons assuming a particular type of sittingposition; the seat portion position for each person substantiallycorresponding to the seat portion height and inclination adjusted to thecomfort of the seated person; the back portion position for each personsubstantially corresponding to the back portion inclination andpositioning, relative to the seat portion positioning, adjusted to thecomfort of the seated person; and the seat and back portion contours foreach person substantially corresponding to contours adjusted to thecomfort of the seated person, with the back portion having athree-dimensional contour substantially corresponding to that formed bythe exposed forward ends of a plurality of unbiased, mutuallyindependent, closely spaced and forwardly extending back plungers,movable to individually adjusted positions, when such back plungers havebeen individually manually adjusted to unyieldingly and independentlyengage and firmly support the back of the seated person in a comfortableposition, and with the seat portion having a three-dimensional contoursubstantially corresponding to that formed by the exposed upper surfacesof a plurality of mutually independent, closely spaced and verticallydisposed seat plungers which are independently movable and equally andindividually resiliently urged upwardly when the person is seated on theupper surfaces of said seat plungers while the persons back is firmlysupported by said back plungers in the manner described.

References Cited in the file of this patent UNITED STATES PATENTS 97,579Wittram Dec. 7, 1869 958,356 Bode May 17, 1910 2,549,902. Hibbard et a1.Apr. 24, 1951 2,847,061 Morton Aug. 12, 1958

1. A CHAIR HAVING BODY SUPPORTING SEAT AND BACK PORTIONS, SAID PORTIONSHAVING THREE-DIMENSIONAL CONTOURS AND RELATIVE POSITIONS SUBSTANTIALLYCORRESPONDING TO THE CONTOURS AND POSITIONS DETERMINED FOR A PERSONASSUMING A PARTICULAR TYPE OF SITTING POSITION, SAID SEAT PORTIONPOSITION SUBSTANTIALLY CORRESPONDING TO THE SEAT PORTION HEIGHT ANDINCLINATION ADJUSTED TO THE COMFORT OF THE SEATED PERSON, SAID BACKPORTION POSITION SUBSTANTIALLY CORRESPONDING TO THE BACK PORTIONINCLINATION AND POSITIONING, RELATIVE TO THE SEAT PORTION POSITIONING,ADJUSTED TO THE COMFORT OF THE SEATED PERSON; AND THE SEAT AND BACKPORTION CONTOURS SUBSTANTIALLY CORRESPONDING TO CONTOURS ADJUSTED TO THECOMFORT OF THE SEATED PERSON, WITH THE BACK PORTION HAVING ATHREE-DIMENTIONAL CONTOUR SUBSTANTIALLY CORRESPONDING TO THAT FORMED BYTHE EXPOSED FORWARD ENDS OF A PLURALITY OF UNBIASED, MUTUALLYINDEPENDENT, CLOSELY SPACED AND FORWARDLY EXTENDING BACK PLUNGERS,MOVABLE TO INDIVIDUALLY ADJUSTED POSITIONS, WHEN SUCH BACK PLUNGERS HAVEBEEN INDIVIDUALLY MANUALLY ADJUSTED TO UNYIELDINGLY AND INDEPENDENTLYENGAGE AND FIRMLY SUPPORT THE BACK OF THE SEATED PERSON IN A COMFORTABLEPOSITION, AND WITH THE SEAT PORTION HAVING A THREEDIMENSIONAL CONTOURSUBSTANTIALLY CORRESPONDING TO THAT FORMED BY THE UPPER SURFACES OF APLURALITY OF MUTUALLY INDEPENDENT, CLOSELY SPACED AND VERTICALLYDISPOSED SEAT PLUNGERS WHICH ARE INDEPENDENTLY MOVABLE AND EQUALLY ANDINDIVIDUALLY RESILIENTLY URGED UPWARDLY WHEN THE PERSON IS SEATED ON THEEXPOSED UPPER SURFACES OF SAID SEAT PLUNGERS WHILE THE PERSON''S BACK ISFIRMLY SUPPORTED BY SAID BACK PLUNGERS IN THE MANNER DESCRIBED.